Fig. 4

Liner rotation and stem rotation of the phantom (a) and patient (b). Dashed lines show stem movements as indicated by the pictogram. In the phantom, liner movement (solid lines) occurs in the end range of modified FABER motion (at 4 and 12 s) and of modified FADIF motion (at 8 s) when the liner/neck angle (black) approaches 36.6° (solid red). In the patient, liner movement occurs in the end range of modified FABER motion (at 4 s) without the liner/neck angle approaching 36.6°